This is a note to let you know that I've just added the patch titled powerpc/memhotplug: Add add_pages override for PPC to the 5.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: powerpc-memhotplug-add-add_pages-override-for-ppc.patch and it can be found in the queue-5.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From ac790d09885d36143076e7e02825c541e8eee899 Mon Sep 17 00:00:00 2001 From: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxx> Date: Wed, 29 Jun 2022 10:39:25 +0530 Subject: powerpc/memhotplug: Add add_pages override for PPC From: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx> commit ac790d09885d36143076e7e02825c541e8eee899 upstream. With commit ffa0b64e3be5 ("powerpc: Fix virt_addr_valid() for 64-bit Book3E & 32-bit") the kernel now validate the addr against high_memory value. This results in the below BUG_ON with dax pfns. [ 635.798741][T26531] kernel BUG at mm/page_alloc.c:5521! 1:mon> e cpu 0x1: Vector: 700 (Program Check) at [c000000007287630] pc: c00000000055ed48: free_pages.part.0+0x48/0x110 lr: c00000000053ca70: tlb_finish_mmu+0x80/0xd0 sp: c0000000072878d0 msr: 800000000282b033 current = 0xc00000000afabe00 paca = 0xc00000037ffff300 irqmask: 0x03 irq_happened: 0x05 pid = 26531, comm = 50-landscape-sy kernel BUG at :5521! Linux version 5.19.0-rc3-14659-g4ec05be7c2e1 (kvaneesh@ltc-boston8) (gcc (Ubuntu 9.4.0-1ubuntu1~20.04.1) 9.4.0, GNU ld (GNU Binutils for Ubuntu) 2.34) #625 SMP Thu Jun 23 00:35:43 CDT 2022 1:mon> t [link register ] c00000000053ca70 tlb_finish_mmu+0x80/0xd0 [c0000000072878d0] c00000000053ca54 tlb_finish_mmu+0x64/0xd0 (unreliable) [c000000007287900] c000000000539424 exit_mmap+0xe4/0x2a0 [c0000000072879e0] c00000000019fc1c mmput+0xcc/0x210 [c000000007287a20] c000000000629230 begin_new_exec+0x5e0/0xf40 [c000000007287ae0] c00000000070b3cc load_elf_binary+0x3ac/0x1e00 [c000000007287c10] c000000000627af0 bprm_execve+0x3b0/0xaf0 [c000000007287cd0] c000000000628414 do_execveat_common.isra.0+0x1e4/0x310 [c000000007287d80] c00000000062858c sys_execve+0x4c/0x60 [c000000007287db0] c00000000002c1b0 system_call_exception+0x160/0x2c0 [c000000007287e10] c00000000000c53c system_call_common+0xec/0x250 The fix is to make sure we update high_memory on memory hotplug. This is similar to what x86 does in commit 3072e413e305 ("mm/memory_hotplug: introduce add_pages") Fixes: ffa0b64e3be5 ("powerpc: Fix virt_addr_valid() for 64-bit Book3E & 32-bit") Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx> Reviewed-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx> Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20220629050925.31447-1-aneesh.kumar@xxxxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/powerpc/Kconfig | 4 ++++ arch/powerpc/mm/mem.c | 33 ++++++++++++++++++++++++++++++++- 2 files changed, 36 insertions(+), 1 deletion(-) --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -353,6 +353,10 @@ config ARCH_SUSPEND_NONZERO_CPU def_bool y depends on PPC_POWERNV || PPC_PSERIES +config ARCH_HAS_ADD_PAGES + def_bool y + depends on ARCH_ENABLE_MEMORY_HOTPLUG + config PPC_DCR_NATIVE bool --- a/arch/powerpc/mm/mem.c +++ b/arch/powerpc/mm/mem.c @@ -104,6 +104,37 @@ void __ref arch_remove_linear_mapping(u6 vm_unmap_aliases(); } +/* + * After memory hotplug the variables max_pfn, max_low_pfn and high_memory need + * updating. + */ +static void update_end_of_memory_vars(u64 start, u64 size) +{ + unsigned long end_pfn = PFN_UP(start + size); + + if (end_pfn > max_pfn) { + max_pfn = end_pfn; + max_low_pfn = end_pfn; + high_memory = (void *)__va(max_pfn * PAGE_SIZE - 1) + 1; + } +} + +int __ref add_pages(int nid, unsigned long start_pfn, unsigned long nr_pages, + struct mhp_params *params) +{ + int ret; + + ret = __add_pages(nid, start_pfn, nr_pages, params); + if (ret) + return ret; + + /* update max_pfn, max_low_pfn and high_memory */ + update_end_of_memory_vars(start_pfn << PAGE_SHIFT, + nr_pages << PAGE_SHIFT); + + return ret; +} + int __ref arch_add_memory(int nid, u64 start, u64 size, struct mhp_params *params) { @@ -114,7 +145,7 @@ int __ref arch_add_memory(int nid, u64 s rc = arch_create_linear_mapping(nid, start, size, params); if (rc) return rc; - rc = __add_pages(nid, start_pfn, nr_pages, params); + rc = add_pages(nid, start_pfn, nr_pages, params); if (rc) arch_remove_linear_mapping(start, size); return rc; Patches currently in stable-queue which might be from aneesh.kumar@xxxxxxxxxxxxx are queue-5.15/powerpc-memhotplug-add-add_pages-override-for-ppc.patch